Composite crank shaft



lJune 18, 1929. L J, MAR-[1N ET AL. 1,717,572

COMPOSITE CRANK SHAFT Filed Aug. 2, 1928 A'TTORNEY Patented June 18, 1929.

UNITED s'rATEs'PA'TENT oFFlcE.

LEONARD J. MARTIN AND CLAIRE L. MARTIN, OF GRENFIELD, CALIFORNIA,

COMPOSITE CRANK SHAFT.

Application filed August 2, 1928. Serial No. 297,078.

Our invention relates broadly to crankshafts for power plants, but more particularly to a built up crank-shaft that is highly adaptable for use in such mechanism as au- 5 tomotive vehicles, air-craft, speed-boats and the like. The chief object of our invention is to pro- 4vide a composite crank-shaft built of sectional arms, pins, bearings and associated parts, so constructed that all working parts are provided with anti-fricton elements, said elements being removable individually without disturbance to the associated parts. v

Further objects will appear as thespecication unfolds. v

We, the inventors, handle garage service, and the present invention is the outcome of our almost daily experience of replacing burnt-out auto crank-shaft bearings,mostly all emergency cases where the people requiring the service are forced to wait for consid- .e1-able time while the 'machinery is being Itaken apart and reassembled to effect the repairs; whereas, by the use. 4of our invention r .there are no bearings to burn out., True,

'there are ball or roller-bearings, but according to our improved and novel construction these can be taken out and new stock-parts7 substituted in a few moments without having to take apart any ofthe machinery except the part immediately involved. l

lVe attain these objects by the mechanism illustrated-in the accompanying drawings, in which Figure 1 is a reduced elevational general view of our crank-shaft with port-ions cut away. x

Fig. 2 isan elevational view of two crankarms cut away at the upper portion thereof along the line III-III of Fig. 3.

Fig. 3 is a. side elevation'of Fig. 2 with one crankarm removed along the line II-H of Fig. 2.

Fig. 3A is a sectional view of an end ele r ment. i

Fig. 4 is an end view of an anti-frictional element.

Fig. 5 is a section of Fig. 4 taken on the line IV-IV- Similar reference characters refer to simi? lar parts throughout the several views. l

In the drawing the numeral 1 designates a supporting frame, 2, 2, 2, the main bearings, 3, the crank-arms, 4 the antifrictional elements.

By reference to 1 it will be seen that the various arms 3 are arranged to operate the connecting rods 5, 5, 5, and 5 that are conbetween said pins 6-and the various straps` 7---7a as is well shown in Fig. 2'.

The arms 3 are of suitable lengths to make up in desired pairs and are provided at each end thereof with the perforations 8, the walls of said perfor-ations being furnished with the splines or key-seats 9, the vertical walls thereof being preferably disposed parallel to each other asl indicated by the ld'otted lines in Fig. 3, the same being for convenience of manufacture.

Now, byreference to Fig. 2 it is seen that the pin 6 serves .to bind the crank-arms 3 together, and also as the carrying member for the antifrictional elements`4 which transmit energy to the connecting rods 5.

.The pin 6 has the longitudinal, regularly spaced grooves 10 formed on its outer surface so as to leave the longitudinal ribs 9a between said grooves, said grooves and iribs being counter-parts and complements of the splines or key-seats 9 formed in the perforations 8 said parts being adapted to coincide with each other as a. perfect fit, so that by gentle tapping blows the said pin may be driven into any pair of said crank-arms so as to form a very rigid connecting member therefor.

At a suitable distance. "from each end therey of said pin 6 is turned down in diameter to the bottom of said grooves so as to leave a reduced cylindrical portiony from the points 12 outwardly which are screw-threaded a-t II-Il to engage the nuts 16 and 16a.

Another very important feature of our in vention is the inner member 12b of the antivfrictional elements 4.

Asis well shown in Figs. 4 and 5 said member *is provided Ion its outer clrcumference with the race means 13 which is adapted to co-act with the rollers 14, and the outerv member 17 or it may be formed as shown in Fig. 2 at 13a as being adapted to accommodate a plurality 0f balls as 4.

However in general appearance said member 12b is a cylindrically-shaped ring whose ilo completely through both said arms 3 and the member 121 right or left from either direction. It should .be noted' that when the nuts 16 and 16a (Figs. 1 and 2) are driven up tight f the inner surfaces of the crank-arms 3 3 are drawn -With great force against the end surfaces 15-15a of the member 12", Whichsaid surfaces are free to do as the shoulders 12-12 ofthe pin 6 do not extend far enough to' interfere, being purposely eut a trifle short.

The outer members 17 of the anti-frictional elements 4 arel closely fitted in the strap mem bers Tand 7i respectively, which are secured in place bybolt means 18-18.

The pins 19 of the outer main bearings are substantially identical with the pins 6 except that they may be provided at one end thereof with the extensions 19-19"that are turned off smooth with the vbottom of the screwthreads 11 as shown in Fig. 1.

In order to explain the Working of the present invention and the advantages thereof it is necessary to point out the novelties of construction involved and the interrelation of parts and method of assembling the same.

The crank-arms 3 may be provided with any desirable number of-"splines or key-seats 9, Figures 2 and 3 show twelve, twelve being a convenient'number to factor, so that the various crank elements may be set at various angles, whereas, Figs. 4 and 5 show six splines. j

Whatever the number of said splines may be the same number must naturally obtain in the corresponding pin 6 and in the member 12b.

AWhen assembling, the first thing is to insert one end of anyjpin in the perforation 3A and byl tapping it lightly drive said pin through said arm far enough to admit of the v member 12b complete with the remainder of the anti-frictional elements such as the rollers .14 and the outer member 17 being also tapped Y lightly on the protruding portion `of said crank 3. Next, the companion crank-arm is 'tapped 'on `to saidpin 6, being careful to see that said arms lie in thesaine plane. Now, by screwingvon the nuts 16 and drawing up evenly on each end of saidpin the inner surfaces of said arms as previously explained) are jammed tight against the respective end surfaces l5 and 15a of the member 12b Whereby a most rigid construction is attained.

vObviously the remainder of said crank may be built up in a similar manner by engagement of the pairs of said vcranks with the eoiresponding pins 6to secure the relative degree with respect to the circle according to the number of cranks required.

4, which in every case may be instantly iemoved by the removal of onenut as 16 or 16n from the pin 6 which allows said pin to be moved axially which admits of a neyv stock part being substituted.

It is believed that the construction, operation and advantages of the invention will now be clearly understood.V The present einbodiments of the invention have been disclosed in detail-merely byv way of example, since in actual practice they attainl the features of advantage set forth as beingdesirable in the statement of the invention and the above description.

Numerous changes in the details of con-- struction, an'd in the combination and ai'- rangement of parts .may be resorted to Without departing from the spirit or scope of the invention as hereinafter claimed or sacrificing any of its advantages;

Having thus described our invention, what We claim as new is l. A crank-shaft comprising a pair of crank-shaft end members, each provided with a body portion having a series of longitudinally disposed groovesand ribs for the entire length thereof, a series of crank-pins each provided with a body portion having a series of longitudinally disposed grooves and ribs for the entire length thereof, a series of crankarms, each arm having a pair of transverse perforations parallel to each other, cach of the perforations having a series of grooves land ribs counterparts of the grooves and ribs on thel body portions of said end members and said crank-pins, an anti-frictional element 'whose inner member provided with grooves and ribs also counterparts of the grooves and. ribs on the body portions of said end members and said crank-pins and means to bind said members, pins and parts securely together.

2. In a crank-shaft as set forth in claim l,

an end member 'suitably reduced and threaded for counterpart nut means, so spaced apart that when screwed home the innersurfaces of said crank-arms will abut the end surfaces 

